Adhesive dispensing apparatus



May 28, 1963 R. B. DUNLAP ADHESIVE DISPENSING APPARATUS Filed Aug. 3,1960 p a. m m G m p I I F a w a w o m ymkz J 0Z/ /0 wk 2 A a 1 J B 0/ am-Ll 6 4/, m. P a 0 a WW w i BY Max "M FIG.5

ATTORNEYS United States Patent 3,091,233 ADHESIVE DISPENSING APPARATUSRobert B. Dunlap, Medway, Mass., assignor to Jacob S. Kamborian, WestNewton, Mass. Filed Aug. 3, 1960, Ser. No. 47,284 2 Claims. (Cl.126-3435) This invention relates to apparatus for providing a supply ofmolten thermoplastic adhesive to a receptacle in which an applicator maybe thrust to pick up a quantity of molten adhesive.

The principal objects of the invention are to provide an apparatus inwhich a body of molten adhesive may be kept ready for instant use, toprovide an apparatus which will supply molten adhesive to an applicatorat a temperature suflicient to maintain desired working viscosity of theadhesive, and to provide an apparatus which will melt the adhesive fromthe solid state and supply the molten adhesive to .the applicator at arate commensurate with the rate at which the applicator picks up themolten adhesive.

As herein disclosed, the apparatus comprises a receptacle having ashallow bowl for retaining a supply of adhesive. The receptacle hasheating elements positioned beneath the bowl for maintaining theadhesive in the bowl molten. A container for a solid block of adhesiveis positioned above the receptacle, and .a conduit is provided thatextends from the bottom wall of the container towards the bowl. A valveis positioned in the conduit intermediate the ends thereof to regulatethe flow of molten adhesive through the conduit and heating elements areprovided between the bottom wall of the container and the valve formelting the block of .adhesive from its bottom .and keeping the adhesivemolten as it gravitates down the conduit and through the valve.

An applicator having a tip is provided for picking up a quantity ofadhesive from the bowl and transporting it to :a work piece to bebonded. By regulating the flow of adhesive through the conduit, one canensure that the molten adhesive is supplied to the bowl at a ratecommensurate with the rate that the applicator picks up adhesive fromthe bowl.

This invention will now be described in greater detail with reference tothe accompanying drawing wherein:

FIG. 1 is a vertical view, partly in section, of the apparatus;

FIG. 2 is a front elevation of the apparatus;

FIG. 3 is a view partly in section on an enlarged scale of the valve andthe control rod therefor;

FIG. 4 is a view taken along line 4-4 Olf FIG. 3; and

FIG. 5 is a view on an enlarged scale of the conduit and valve.

Referring to the drawing the apparatus has a base underlying areceptacle 12. A housing 14, preferably of sheet metal, is positionedbeneath the base and extends upwardly from its sides. A cover plate 16,also preferably of sheet metal, is positioned above the base and issecured to the housing 14 by screws 18. The receptacle 12, base 10, andhousing 14 are secured to each other by headed bolts that extend throughaligned openings in the housing and base and are screwed into threadedopenings in feet 22 of the receptacle 12. The heads of the bolts 20serve as feet to support the apparatus. Insulating material 24, such asFiberglas, provided in the space between the base 10, receptacle 22,housing 14 and cover plate 16.

The upper surface of the receptacle 12 has a shallow bowl 26 therein forretaining molten adhesive. The portion 28 of the receptacle extendingforwardly of the bowl is raised and has a notch 30 therein forsupporting an applicator thrust into the bowl. An opening is provided inthe cover plate 16 to accommodate the upper portions of the receptacle12 including the bowl 26 and the portion 28. A hood 31, secured to thereceptacle by screws 32, is positioned over the bowl. The hood serves tokeep dirt out of the .bowl and to act :as an insulator for the moltenadhesive in the bowl. Three electrically operated heating elements 34are positioned in the receptacle below the bowl 26.

A container 36 is mounted above the receptacle on a pair of legs 38, thelower ends of said legs being screwed into the receptacle, The containercomprises a frame 40 having :a cavity 42. The cavity is cylindrical inform and is adapted to retain a cylindrical block of solid adhesive. Alining 44, preferably of sheet metal, is secured to frame 40 by screws46. The lining is cylindrical in form, extends upwardly from the frame,and is concentric, to, but of a larger diameter than, the cylindricalwall of the cavity. The upper portion 48 of the lining overlies theframe and has an opening 49 aligned with the cavity 42. Insulatingmaterial 51, such as Fiberglas, is inserted between the cylindricalwalls of the cavity and the lining.

A hole 50 extends from the bottom wall 53 of the cavity 42 to the bottomof the frame 40. A valve housing 52 is threaded into the lower end ofthe hole 50, said valve housing having a hole 54 extending therethrough.The lower end of the hole 54 is positioned above the bowl 26.

An opening 56, transverse to and intersecting the hole 54, is providedin the valve housing 52. A valve 58 is rotatably mounted in the opening56. The valve 58 has a hole 60 extending therethrough which in oneposition of adjustment is aligned with the hole 54 and in a secondposition of adjustment is transverse to the hole 54, thus enabling thevalve to block the hole 54. The valve has a flange 62 at one end, whichis of greater diameter than the main valve portion 64. The flange has aperipheral portion 66 of relatively large diameter and a peripheralportion 68 of relatively small diameter, both peripheral portions beingsegments of circles. Abutmen-ts 70 are formed at the intersection ofperipheral portions 66 and 68. A pin 72 is secured to the valve housing52 in such a position that it can ride on the peripheral portion 68 whenthe valve is rotated. The valve has a stud 74 extending outwardlytherefrom at the end remote from the flange 62. A rod '76, having a knob78 fastened thereto, is threaded on to the stud 74.

A pair of electrically operated heating elements $0 are located in holesextending through the frame -40 on opposite sides of the hole 50. Theheating elements 80 and the aforementioned heating elements 34 areelectrically connected to a junction box 82 located in an opening in thereceptacle 12. An adhesive applicator 84 for picking up a quantity 01fmolten adhesive from the bowl 26 is also electric-ally connected to thejunction box. The applicator may be of the type disclosed in applicationSerial Number 20,461 filed April 6, 1960. A line (i6 extends from thejunction box 82, to the source of power. Optionally, a temperatureresponsive switch 83 may be provided to control the heating elements.

The apparatus is intended to supply molten adhesive to the receptacle sothat the molten adhesive may be picked up by the applicator and appliedto the parts of a workpiece, such as a shoe, as a part of the process ofadhesively bonding the parts together. Reference is made to applicationSerial Number 28,408 filed May 11, 1960, for an example of such aprocess. The adhesives currently used for this purpose are relativelyquick setting, that is a relatively small change in temperature willcause the molten adhesive to transform into the solid state. However,should the molten adhesive be exposed to the atmosphere, or remainmolten at a rela- I adhesive flow at the desired rate.

tively high temperature for a relatively long period, it is subject tothermal decomposition and oxidation which causes the adherent qualitiesof the adhesive to deteriorate. On the other hand, the adhesive must beat a relatively high temperature when it is applied to the work parts tohave the desired working viscosity.

In using the apparatus, a block of solid adhesive is placed in thecavity 42. The block is preferably cylindrical in form and of a diametercorresponding to the diameter of the cavity. The heating elements 80melt the block of adhesive from the bottom and the molten adhesivegravitates down the conduit formed by the holes 56 and 54 into the bowl26. The adhesive collected in the bowl is heated by heating elements 34to cause it to remain molten, the adhesive being kept hot enough toenable it to retain the desired working viscosity. The applicator 84 isnormally resting in notch 30 with the tip 90 of the applicator supportedby the bottom of bowl 26 and immersed in the molten adhesive in thebowl. When adhesive is to be applied to the work, the operator lifts upthe applicator, whereby the applicator tip picks up a quantity ofadhesive, carries the applicator to the work and rubs the applicator tipalong the work, thereby depositing a quantity of adhesive on the work.

As set forth above, if the molten adhesive remains in the bowl too long,it tends to deteriorate. To prevent this, the operator can adjust thevalve 58 so that molten adhesive gravitates into the bowl atapproximately the same rate as it is picked up by the applicator tip. Bymanipulating knob 78, the valve can be rotated from the position shownin FIGS. 1 and 5 where pin 72 is in engagement with left abutment 70(FIG. 5) and hole 69 is aligned with hole 54 to a position where the pin72 is in engagement with the right abutment 70, the hole 60 ishorizontal and the hole 54 is blocked by the valve 58. The valve can, ofcourse, be adjusted by the manipulation of the knob 78 between the twoextremes of full flow of adhesive and no flow of adhesive to set the Thelocation of the heating elements St) between the bottom wall of thecavity 42 and the valve 58 causes the block of adhesive in the cavity tobe melted from the bottom and causes the heat to be applied to the valveand to the hole 54, thereby ensuring that the adhesive will not solidifyduring its passage through the holes 50, 54 and 60.

Ideally, heating elements 80 give off enough heat to melt the adhesiveand maintain it in its molten condition during its passage through holes50, 54 and 60, and heating elements 34 give off enough heat to maintainthe adhesive in the bowl 26 at the higher temperature which issuflicient to give the adhesive the desired working viscosity. One ormore temperature responsive switches 88 may be provided for thispurpose.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsthat come within the scope of the appended claims.

I claim:

1. An adhesive dispensing apparatus comprising: a receptacle; a bowl inthe upper surface of the receptacle for retaining a supply of moltenadhesive, and from which a quantity of the molten adhesive may be pickedup by an applicator; first heating means located in the receptacleadjacent the bowl for maintaining the adhesive in the bowl molten; acontainer for a quantity of solid adhesive positioned above thereceptacle, said container including a cavity having abottorn wall; aconduit extending downwardly from the bottom wall toward the bowl forconducting molten adhesive from the cavity to the bowl; adjustable valvemeans in the conduit for regulating the rate of .flow of molten adhesivetherethrough; and second heating means positioned below said bottom walland adjacent said valve means for melting the solid adhesive in thecavity from the bottom and maintaining the adhesive molten during itspassage through the conduit.

2. An adhesive dispensing apparatus comprising: a receptacle; a bowl inthe upper surface of the receptacle for retaining a supply of moltenadhesive and from which a quantity of the molten adhesive may be pickedup by an applicator; a raised portion on said receptacle extendingupwardly of the bowl adjacent the bowl and having a notch adapted tosupport the applicator; at least one heating element positioned in thereceptacle beneath the bowl for maintaining the adhesive in the bowlmolten; a frame positioned above the receptacle, said frame including acavity having a bottom wall; a hole extending through the frame from thebottom wall to the bottom of the frame; a valve housing secured to theframe, said valve housing having a hole extending therethrough inalignment with the hole in the frame, the valve housing being so locatedthat its lower end is positioned above the bowl; a valve rotatablymounted in the valve housing, said valve having a hole extendingtherethrough so that in one extreme position of valve adjustment thehole in the valve is in alignment with the holes in the frame and thevalve housing, in a second extreme position of valve adjustment thevalve blocks the hole in the valve housing, and in a median position ofvalve adjustment intermediate said extreme positions the valve partiallyblocks the hole in the valve housing; and at leastone heating elementpositioned in said frame between said bottom wall and said valve formelting a quantity of solid adhesive positioned in the cavity from thebottom and maintaining the adhesive molten during its passage throughsaid holes into the bowl.

References Cited in the file of this patent UNITED STATES PATENTS2,544,661 Fossa Mar. 13, 1951 2,564,427 De Rugeris Aug. 14, 19512,665,823 Fossa Jan. 12, 1954 2,678,146 Schleif May 11, 1954 2,773,496Czarnecki Dec. 11, 1956 2,957,440 Schaefer Oct. 25, 1960 2,979,234Kamborian Apr. 11, 1961 2,995,159 Berggren Aug. 8, 1961

1. AN ADHESIVE DISPENSING APPARATUS COMPRISING: A RECEPTACLE; A BOWL INTHE UPPER SURFACE OF THE RECEPTACLE FOR RETAINING A SUPPLY OF MOLTENADHESIVE, AND FROM WHICH A QUANTITY OF THE MOLTEN ADHESIVE, MAY BEPICKED UP BY AN APPLICATOR; FIRST HEATING MEANS LOCATED IN THERECEPTACLE ADJACENT THE BOWL FOR MAINTAINING THE ADHESIVE IN THE BOWLMOLTEN; A CONTAINER FOR A QUANTITY OF SOLID ADHESIVE POSITIONED ABOVETHE RECEPTACLE, SAID CONTAINER INCLUDING A CAVITY HAVING A BOTTOM WALLTOWARD THE EXTENDING DOWNWARDLY FROM THE BOTTOM WALL TOWARD THE BOWL FORCONDUCTING MOLTEN ADHESIVE FROM THE VACITY TO THE BOWL; ADJUSTABLE VALVEMEANS IN THE CONDUIT FOR REGULATING THE RATE OF FLOW OF MOLTEN ADHESIVETHERETHROUGH; AND SECOND HEATING MEANS POSITIONED BELOW SAID BOTTOM WALLAND ADJACENT SAID VALVE MEANS FOR MELTING THE SOLID ADHESIVE IN THECAVITY FROM THE BOTTOM AND MAINTAINING THE ADHESIVE MOLTEN DURING ITSPASSAGE THROUGH THE CONDUIT.